In the prior art, with an electronic camera set to a high sensitivity (for example, by raising the output gain of an image pickup device), a shot image will have an increase in noise such as coarse noises, and show color speckles. Such noises can be reduced by smoothing the image. However, excessive smoothing damages a fine image structure of an object, so that the image will not have good texture.
There is a known device that compensates for such deterioration in texture as shown in the following patent document 1.
According to the patent document 1, a minute amplitude component is extracted from image data to add the minute amplitude component to the image data. This prior art technique enables texture emphasis, so-called “wrinkle emphasis”.
Patent document 1: Japanese Unexamined Patent Application Publication No. 2001-118064 (for example, FIG. 5)